Single women trail only married couples as the biggest demographic group buying homes, according to Mark J. Penn's book Microtrends. In 2005, single women bought 1.5 million homes--more than twice the number that single men bought, Penn wrote.

As a result, "Home maintenance, home repair, and home security companies have an enormous new market to attend to in single women," Penn wrote.

What is the reason for this? There are many, of course, but Penn focuses his analysis on one in particular: there are simply more straight women than there are straight men. Part of the reason for that is that "gay men outnumber lesbians in America by approximately 2 to 1," Penn wrote. Further, more males die before adulthood than do females. Penn wrote that researchers attribute this to a phenomenon called the "'testosterone storm,' which causes more deaths among boys from car accidents, homicides, suicides, and drownings."

What all of that that means, as in musical chairs, is that some women are simply going to be left out.

In addition to the fact that there are just more single women than there are single men, there are a couple other reasons that could be influencing the vast number of single women who are buying homes. One is that single women stay single longer than they used to. "In the last decade the median age for marriage has increased by one year to 26.7 years for men and 25.1 for women," according to a study released by the U.S. Census Bureau in 2005.

Women are also gaining ranks in both college and the workforce. "From 1970 to 2000 the number of women completing college has nearly doubled and the number in the labor force has gone up by almost 40 percent," according to the National Center for Health Statistics.

Thus, with more women receiving college educations and then entering the workforce, there are more women than ever with enough money to purchase and maintain their own homes--and even more women who are becoming real estate investors. For more on that, see our article Women Investing in Real Estate.